In case of an airplane or helicopter emergency landing a rapid increase of vertical accelerations acting to the human is occurred, which could lead to serious damage of a spine. In order to counteract this danger aircraft seats are equipped with different types of shock-absorbing systems and crumple zones increasing crash safety by absorbing energy acting on a pilot. In lightweight flying designs the aim is to seek such solutions that increase the safety level while maintaining a minimum weight and dimensions of the seat.
Patent Application US 2013229038 describes the construction of a seat, wherein the sitting part made of a metal sheet has side portions which are double bent in such a manner that in the result of the exerted force it develops absorbing a part of the energy. The side portions may be further joined by rivets fixing the bent part during normal use. When the assumed force is exceeded the rivets fall out and the bent portion is straightened and absorbs a part of the force acting on the pilot pelvis and lowers the position of the sitting part by a few centimeters.
From U.S. Pat. No. 6,896,324 an aircraft seat is known having an ergonomically formed sitting part coupled to the sides and to the backrest provided with structural elements which undergo the controlled plastic deformation under influence of an overload. The upper panel of the sitting part can be downwardly deformed and absorbs a part of the energy induced by a vertical acceleration. Under the upper panel of the seat an absorber is arranged forming a crumple zone, which, after deformation of the upper panel, absorbs a part of the crash energy. The absorber is supported by a lower panel of the seat attached to the sides. The absorber may be made of aluminium in the form similar to a honeycomb or from other energy absorbing materials, such as plastic foam materials. A part of the energy can also be absorbed by the properly made seat sides to which the sitting part is attached.
The object of the invention is to provide a lightweight seat structure characterized by an increased safety level.